Add Field Trial for Prerender From Omnibox.

BUG=95066
TEST=None


Review URL: http://codereview.chromium.org/7825009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@101963 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 48 insertions, 2 deletions

diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index 9153eba..ba7184f 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -8,13 +8,19 @@
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
-#include "content/browser/renderer_host/resource_dispatcher_host.h"
+#include "chrome/browser/metrics/metrics_service.h"
+#include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
-
+#include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 namespace prerender {
 
+// If the command line contains the --prerender-from-omnibox switch, enable
+// prerendering from the Omnibox. If not, enter the user into a field trial.
+void ConfigurePrerenderFromOmnibox();
+
 void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
   enum PrerenderOption {
     PRERENDER_OPTION_AUTO,
@@ -117,6 +123,46 @@ void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
   UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
                             PrerenderManager::GetMode(),
                             PrerenderManager::PRERENDER_MODE_MAX);
+
+  ConfigurePrerenderFromOmnibox();
+}
+
+void ConfigurePrerenderFromOmnibox() {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kPrerenderFromOmnibox)) {
+    const base::FieldTrial::Probability kDivisor = 100;
+    const base::FieldTrial::Probability kEnabledProbability = 10;
+
+    scoped_refptr<base::FieldTrial> trial(
+        new base::FieldTrial("PrerenderFromOmnibox", kDivisor,
+                             "OmniboxPrerenderDisabled", 2012, 8, 30));
+
+    trial->AppendGroup("OmniboxPrerenderEnabled", kEnabledProbability);
+  }
+}
+
+bool IsOmniboxEnabled(Profile* profile) {
+  if (!profile || profile->IsOffTheRecord())
+    return false;
+
+  if (!PrerenderManager::IsPrerenderingPossible())
+    return false;
+
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kPrerenderFromOmnibox)) {
+    return true;
+  }
+
+  if (!MetricsServiceHelper::IsMetricsReportingEnabled())
+    return false;
+
+  const int group = base::FieldTrialList::FindValue("PrerenderFromOmnibox");
+  if (group == base::FieldTrial::kNotFinalized ||
+      group == base::FieldTrial::kDefaultGroupNumber) {
+    return false;
+  }
+
+  return true;
 }
 
 }  // namespace prerender